Hyperbaric Oxygen/Oxidative Stress

I'm exploring the possibility of doing mild hyperbaric oxygen therapy (HBOT), because I've heard that it can help. What I don't understand, though, is how can something that oxidizes help when CFS/ME is a disease of oxidative stress? I'm sure I'm revealing my ignorance with this question, but if anyone understands it better than I do, please explain! Thanx!

I was diagnosed with Obstructive sleep apnea. I brought the results to my CFIDS Dr, and the oxygen levels were low enough that he precribed oxygen of 2L/min (oxygen concentrator, not tanks, less work this way). I have been doing this for over 3 years now.